The invention is based in particular on a replaceable rechargeable battery unit for a power tool which is provided for detachable connection to a power tool. For being charged, the replaceable rechargeable battery unit has a coupling unit, formed by charge contacts. The coupling unit is located on a part of the replaceable rechargeable battery unit that can be inserted into a receptacle region of a power tool. Once the replaceable rechargeable battery unit has been inserted into the receptacle region of the power tool, the coupling unit is covered by the housing of the power tool. For charging the replaceable rechargeable battery unit, this unit must be removed from the receptacle region of the power tool and inserted by the insertable part into a charger.